# Pagerless for AWS Lambda

> Woken only when it matters, and one tap undoes a bad deploy: Pagerless points the alias at the previous version.

URL: https://pagerless.dev/integrations/aws-lambda
Updated: 2026-10-22

## Set up

Node functions: `import "pagerless/auto"`. Python: `@pagerless.aws_lambda.handler` ([Python SDK](https://pagerless.dev/integrations/python)). Any runtime, no code: [CloudWatch alarms over SNS](https://pagerless.dev/integrations/aws-cloudwatch).

Store the key with the function's environment variables. Or run `npx pagerless connect` and it finds your services and places the key for you.

## Fixes on AWS Lambda

| Fix | On AWS Lambda |
| --- | --- |
| Undo the update | Points the alias at the previous version |
| Restart | Not available |
| Add capacity | Changes reserved concurrency |
| Deploy events | Yes: errors right after a deploy are tied to it |
| Access it needs | an IAM role with an external ID |

## Questions

### Can Pagerless roll back AWS Lambda automatically?

Yes, if your rules set undo to alone. By default it asks first, and approving an undo needs your passkey (Face ID or Touch ID). It then points the alias at the previous version.

### Does Pagerless need admin access to AWS Lambda?

It needs an IAM role with an external ID. It is stored encrypted and used only for the fixes listed above. You can skip it: alerts work without it.